Why Doesn't LA Just Put the Fires Out Using Ocean Water?

As the city takes stock of the wreckage, firefighters are still battling several wildfires in the Los Angeles region — and the path of destruction is enormous.

An extremely dry 2024 — inextricable at this point from the consequences of human-caused climate change — has made firefighting efforts even more complicated. Last week, fire hydrants started to run dry, leaving some firefighters empty-handed.

Which leaves an intriguing question: why aren't they scooping up water from the nearby Pacific Ocean?

As Patrick Megonigal, associate director of research at the Smithsonian Environmental Research Center, explains in an essay for The Conversation, dumping saltwater is conventionally only a last resort, reserved for extreme situations.

The answer as to why is twofold. For one, saltwater can accelerate the corrosion of firefighting equipment substantially. Second, saltwater can have devastating effects on the ecosystems where it's dumped, a more insidious and long-term reason why firefighters avoid ocean water.

As Megonigal explains, researchers are only beginning to understand the negative consequences of introducing saltwater in places that are only accustomed to fresh water — a pertinent topic beyond the fires in California, considering that sea levels are on the rise around the globe.

And in fact, the devastation in Los Angeles has been so immense that firefighters have been using ocean water as a last resort.

Last week, firefighters flew aircraft known as Super Scoopers across the surface of the ocean to collect thousands of gallons of water to dump on wildfires, in an extreme measure reserved for when fresh water is extremely hard to come by.

That's because many local ecosystems are only accustomed to freshwater. Introducing salts could have devastating effects on trees alone; for an example, look at the remaining stumps of ghost forests, which are newly created wetlands caused by rising sea levels in coastal areas.

In an experiment dubbed Terrestrial Ecosystem Manipulation to Probe the Effects of Storm Treatments (TEMPEST), Megonigal and his colleagues at the Smithsonian pumped salty water from the Chesapeake Bay into a forested test plot.

Being exposed to the salty water for just 30 hours caused the test plot trees to brown in mid-August, weeks earlier than normal.

"These changes did not occur in a nearby plot that we treated the same way, but with freshwater rather than seawater," Megonigal explained.

They also found that the soil chemistry and structure were altered, with clays and other particles being dissolved, something that generally doesn't happen without the presence of saltwater.

In other words, dumping "full-strength, salty ocean water" in extremely dry areas that are not used to being soaked, like Los Angeles, could have disastrous consequences.

However, there's still plenty to learn about these undesired effects.

"Our research group is still trying to understand all the factors that limit the forest’s tolerance to salty water, and how our results apply to other ecosystems such as those in the Los Angeles area," Megonigal admitted.

However, as sea levels continue to rise, more of the West Coast is being routinely exposed to saltwater, which could pose "unknown risks for coastal landscapes."

In short, the fact that Los Angeles firefighters are resorting to saltwater at all is just another indication of how serious the blazes have been.

More on the fires: Politicians Blame Los Angeles Fires on Explosion of AI Data Centers